Add support for trailing and leading visual icons in Primer::Beta::Link

[HDinger]

What are you trying to accomplish?

This PR adds slots for a trailing_visual and a leading_visual. As of now, only Icons are supported as types.

Screenshots

List the issues that this change affects.

Closes #2981

Risk Assessment

• Low risk the change is small, highly observable, and easily rolled back.
• Medium risk changes that are isolated, reduced in scope or could impact few users. The change will not impact library availability.
• High risk changes are those that could impact customers and SLOs, low or no test coverage, low observability, or slow to rollback.

What approach did you choose and why?

I limited the visual to icons for now, as I did not know, which other types (avatar, svg, ...) shall be supported.

Anything you want to highlight for special attention from reviewers?

I extracted the code of the call method to a html.erb template because of the increased complexity of the template. In there I used a capture block to avoid the previous duplication depending on the existance of a tooltip.

Merge checklist

• Added/updated tests
• Added/updated documentation
• Added/updated previews (Lookbook)
• Tested in Chrome
• Tested in Firefox
• Tested in Safari
• Tested in Edge

[changeset-bot]

🦋 Changeset detected

Latest commit: 681670a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/view-components	Minor

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Click here if you're a maintainer who wants to add another changeset to this PR

[HDinger]

One of the failing tests is checking that there is no leading and trailing white space before the link text. Currently, every linebreak in the erb file is interpreted as white space. The erb syntax allows to strip the trailing white space with -%>. However for leading <%= this is not possible, see the docs.

I currently see two options:

1. Wrapp a span around the content like it is done for buttons.
2. Write the whole link_content in the erb in one line. That would look ugly as hell, but leaves the DOM unchanged.

Let me know what you prefer.

[camertron]

Thanks for this 😄

[camertron]

One of the failing tests is checking that there is no leading and trailing white space

Ah yeah I see what you mean... what if we added a trim: boolean argument to BaseComponent (and ConditionalWrapper) that would automatically call #strip on content before emitting it?

[HDinger]

Hi @camertron

I adressed your remarks and introduced a trim flag which calls strip on the content. The component tests are now green. There are three other tests failing, which I really don't know why. Especially the changeset tests is weird, as there is a changeset added 🤷

[camertron]

the changeset tests is weird, as there is a changeset added 🤷

Ah yeah, that one always fails for forks because it pulls the original repo instead of the forked repo and can't find the branch. It's ok, I can manually override when I merge 👍

[camertron]

Awesome, thank you for your work on this and for persevering through my feedback! 🎉